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Discussing the Open Source FPGA Amiga Project
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 Post subject: Re: More "slow" RAM?
PostPosted: Mon Sep 06, 2010 9:37 am 
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Joined: Mon Dec 01, 2008 9:58 pm
Posts: 1568
Location: .de
Dont rely on sysinfo cpu speed (MHz) output. This test is based on memory access time.
Since the current core provide cpu cache inside the FPGA, the sysinfo benchmark points out nearly the correct speed rate. Actually the cpu ALWAYS is clocked at 49.63MHz in Turbo mode!

If sysinfo can run in "slow ram", the whole test routine is able to run inside the very fast cpu cache. Therefor the speed rate could show more MHz then actually present.

To the memory config of Minimig, wolfchild already point out a reasonable combination list.
Beside that, some old game/demo/cracktro dont like anything else then chip ram. Even less dont like moren then 0.5MB of available chip ram. Then the config should be changed to 0.5MB of Chip and possibly 0.0MB of Slow ram to make those title work.

Since the cpu cache affect slow ram and the rom area, for any Workbench issue the 0.5MB Chip and 1.0MB Slow config would be best for a standard Minimig board.
For an expanded Minimig board, the full size of each memory type is recommendable.

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 Post subject: Re: More "slow" RAM?
PostPosted: Mon Sep 06, 2010 12:55 pm 
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Joined: Thu Jan 29, 2009 9:29 am
Posts: 36
Location: Lorraine - France
Thank you so much Wolfchild and Boing4000 for your explanations

I completely forgot the kickstart cache ! Seems logical now about the errors I get with some settings.
But strange that my "0.5 Mo Chip + 1.5 Mo Slow" settings works... Maybe it's working until it use the range of memory.

wolfchild wrote:
(1.5MB - AR3 off)
1MB chip + 0.5MB slow (more space for chipset data - useful for tools such as DPaint, etc)
0.5MB chip + 1.0MB slow (more space for program data - more chance for software to benefit from cache)
boing4000 wrote:
Since the cpu cache affect slow ram and the rom area, for any Workbench issue the 0.5MB Chip and 1.0MB Slow config would be best for a standard Minimig board.

Now I can chose my preference, thanks.

And I will no trust Sysinfo any more for my Minimig. I understand now that it can't be objective.

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